The present invention relates to controlled depth cartridge case chamfering tool for use in preparing both new cases and the cases of spent firearm cartridges for loading or reloading operations, and in particular to the loading and reloading of rifle cases to furnish cartridges for both high accuracy sport shooting as well as precision bench rest shooting, wherein the tool of instant invention enables one to manually accomplish a gradual truncated conically shaped taper chamfering of a sized and trimmed cartridge case, extending from the case mouth internal circumferential edge to within the neck interior thereof.
One of the standard preparation operations performed in the processing of spent cartridge cases for reloading, which is a procedure well known in the art among those who practice such activity, is that of deburring and reaming a bevel about the interior circumferential case mouth opening of resized and trimmed cases to thereby more easily enable the positioning and receiving of a bullet tip for seating. And, in most pistol and rifle cartridge reloading operations the reaming tool deburring and beveling of cartridge case mouths is both an adequate and satisfactory measure for facilitating bullet tip seating, as well as providing cartridges of satisfactory quality for general purpose hunting and shooting.
Exemplary tools available for accomplishing the ream deburring and beveling of the cartridge case interior circumferential mouth opening, which tools are adjustable to accommodate cases of different sized bullet calibers, would include those as respectively taught in U.S. Pat. No. 4,468,829 to Christensen dated Sept. 4, 1984, and U.S. Pat. No. 4,860,453 to Carroll dated Aug. 29, 1989, both of which tools feature three-bladed scrape-reamers for interior case mouth deburring and bevel cutting to produce a very blunt case mouth entry for bullet tip positioning and seating.
Additionally, the teaching set forth in U.S. Pat. No. 2,359,954 to Whipple dated Oct. 10, 1944, discloses a rotating cutting tool for the deburring of a cartridge case mouth and the chamfering of the internal circumferential edge thereof at a 45-degree angle. Rhine, in U.S. Pat. No. 3,199,168 dated Aug. 10, 1965, teaches an adjustable cartridge case mouth trimming and internal circumferential edge chamfering tool adapted to be used in combination with a power tool drive. The device shown in U.S. Pat. No. 4,686,751 to Gracey dated Aug. 18, 1987, teaches a resized cartridge case neck trimming and case mouth deburring tool which indexes trim completion on the shoulder of a resized case. Again, all of the additional above cited prior art references show tools which bevel the case mouth opening to produce a very blunt case mouth entry for bullet tip positioning and seating, which is adequate in producing cases which will provide cartridges of satisfactory quality for general purpose hunting and shooting.
For those, however, interested in loading or reloading so called "match" ammunition for high accuracy sport shooting or precision bench rest shooting there is an aspect of accuracy potential with respect to cartridge quality that results from the mere scratching, marring, or deforming of the bullet tip base or heel, a hazard inherently resultant from operations performed during the positioning and seating of a bullet tip in accomplishing loading or reloading operations. And, one major contributing cause for such bullet tip base or heel defects results when one attempts to position and seat a bullet tip through a blunt beveled cartridge case mouth opening which is not profiled to incrementally receive a bullet tip for positioning, and subsequently for seating. Thus, if one is able to provide a tapered chamfer at the cartridge case mouth opening, which gradually extends conically down into the neck, rather than a blunt shallow chamfer such as is obtained when using currently available deburring and chamfering tools, then the ease of bullet tip positioning and seating is substantially enhanced with a corresponding reduction in the liklihood of damage to the bullet tip base or heel during such operations, thus enabling the retention of optimum cartridge factor accuracy aspects with regard thereto.
Secondly, there is a technique of bullet tip seating known as "heel seating" which is employed primarily by precision bench rest shooters as a method to even further enhance the cartridge factor accuracy potential, and consists of bullet tip seating within the case neck by periperal contact only of the bullet tip heel lightly about a relatively deep truncated conically shaped neck interior, which further minimizes the potential for bullet tip damage during placement and seating operations, and additionally enables the bullet tip to thereafter conformably seat within the barrel bore of the firearm upon chambering and closing and locking of the firearm action, which additionally enhances cartridge factor accuracy potential by not firing a mechanically stressed bullet. None of the above cited prior art teachings provide the mechanical capability for taper cutting a cartridge case mouth in preparation thereof for the heel seating technique as does the adjustable depth taper chamfering tool disclosed and taught herein by applicant.
Thus, the applicant herein by his invention furnishes a new and novel tool to provide a true cartridge case mouth taper chamfering capability, the use of which enhances substantially the loaded and reloaded cartridge factor accuracy potential by first reducing the liklihood of bullet tip base or heel damage during the placement and seating operation thereof, and also provides a mechanical capability for preparing cartridge cases adapted to employ the heel seating technique for even greater cartridge factor accuracy potential as above described.